stu21t

i went out in an escos last night that has a very similar engine spec to mine (but a std exh cam, i have a bd 10, and he has no headwork, mine does) but is a lot less laggy,
does the fact that my cams (bd10,14) are fully retarded (to make less torque and save my gearbox) have anything to do with this?
his car seemed to start to spool about 1500revs earlier and be on full boost at least 1000 revs earlier than mine
and holds more boost that mine, even tho they should be the same?
and looking at other power graphs on here mine does seeem very laggy compared to others.
could my cam timing have anything to do with this?
what would the difference be if my cams were more advanced?

The Youth.

iTrader: (1)

in answer to the original title question then yes it will effect it.
as the inlet (and exhaust) valves are not open for the required time and amount per cycle then the air has nowhere to go,

steve

Chip

iTrader: (3)

It has a large effect, but there will be an optimum point, and without trial and error it will be impossible to know what that is, so therefore its hard to know which side of it you are currently.
If your cams are as retarded as they sound though, you may well have gone past that point, so try dialing it back a bit, bear in mind that you need to remap it really though if you do.

stu21t

So would having the cams retarded cause more lag?
And would it mean the car makes less boost/turbo has to work harder to make the same boost as a car with cams advanced?

stu21t

It was done to try and make more bhp but less torque to save my gearbox, which it has done but the car seems very laggy and I can only think it's the cam timing.
I'm going to take the car to Msd later in the year for a check over of the map but would like to get it nearer the mark before I go.

Chip

iTrader: (3)

There is an optimum point for spooling the turbo for each cam

More advanced than optimum = more lag
More retarded than optimum = less lag

I dont know what optimum is on each cam on your engine, or what your current timing is, so I cant comment if yours will get better or worse if you advance it with any 100% certainty, but I would *expect* it will get better if you advance it a little if currently its as retarded as it sounds as typically the standard marks arent too far out for relatively early spool.

Also you are considering the two cams together, you will find that the optimum almost certainly has different values on each cam, so really you need to swing each one around one at a time to find the optimum for each.

Bear in mind that you will probably then end up with the extra torque you were trying to avoid though, so will need less boost lower down to avoid it, so will need a boost control setup that will do that.

You will also probably lose top end power, as generally retarding the cams will move the power up the rev range like you have previously been correctly informed.

Chip

iTrader: (3)

I would leave it alone and let them set the cams up instead, as part of the mapping, if you start changing it drastically now, you may cause a problem with the fuelling that could be damaging.

stu21t

That all makes very good sense.
I will let them do it
it's just the cars not fast enough lol
I'm trying to find that extra bit of ooomph and sounds like it might b in the cam timing.
Stupid gearbox.

Chip

iTrader: (3)

Cars go better with a working gearbox than a broken one, so I see no point in extracting mroe power than your gearbox can handle.

stu21t

Looking at my last rr results the car made 0boost at 3000rpm,
0.5bar at 4200, 1bar at 4700, 1.6 at 5200

it should hold 2 bar but I didn't get that far with the rr session as I had fuel pressure probs.

Also at 4500 I only have 175bhp at 5000 I have 300 and 360 at 5200

which makes it fast top end but laggy and slow on the uptake.
Torque curve is very similar

B13 JUS

iTrader: (24)

if you get your car mapped should they be playing about with the cam timing to get the best out of the car?

stu21t

If it's not part of a map/set up
then you ask for it and pay the extra hr or so labour then yes.
On the Msd website it says they visually check timing, not sure what that means really.

Chip

iTrader: (3)

Crikey, that spools later than the GT42R on Rod's car which makes 838bhp

Chip

iTrader: (3)

That would depend on what you discuss with them, typically they WONT touch the cam timing as doing so can wreck the engine if you dont know the clearances, and how could they if they didnt build it?
So most mappers will only touch the cams if specifically asked and they will want you to confirm that there is clearance for them to do so and that if there turns out not to be its YOUR fault not theirs.

stu21t

Told you it was laggy lol
only recently got the car good enough to get this far with it tho lol

could this be down to cam timing?
Everything else seems fine.

JamesH

iTrader: (21)

Yes if you have adjustable verniers, why not? Providing pocketed pistons etc

if not, they surely at least check they're in the standard position?